Adjustable remote controlled video camera

Here is an innovative video surveillance system, comprising, firstly, an orientation unit remotely by radio, with micro-camera, television transmitter and servos and, secondly, a special remote control. In this paper, we present, among others, plans for assembling the steering system made using ordinary hobby servos and a few cuts with epoxy. To our knowledge, there is no equipment of its kind in the trade, even for highly sophisticated facilities. The design was a challenge, you can realize it is a pleasure.

Remote monitoring is a topic we've discussed several times in these pages by offering different types of systems. The purpose of these devices, remote viewing is what happens in one place, office, warehouse, garage, apartment, etc.. In order to react in case of intrusion or abnormal events.
The simplest systems are working "to son": the video camera (whatever that is) is connected to a monitor as well as a video recorder, using a cable that can easily exceed a few tens of meters.
To be able to easily move the camera from one location to another or simply to get rid of the cables, many of these systems operate by radio control: the camera is connected to a low power transmitter whose emission is captured by a receiver connected to the monitor. The best-known systems operate on the frequency band of 2.4GHz, but there are also more economical systems working in the TV bands.
In this case, one can use a regular TV instead of monitor, thus achieving significant economy.
All these systems use video cameras whose focus is fixed and only fit a given area.
Only more sophisticated systems (and therefore more expensive) have the opportunity to cover a much larger area by vertical and horizontal movement of the camera.
If it really means, one can also purchase a video camera equipped with a zoom lens, said automatic switch to change the focal length of optical-zoom x16, x32, x64, x128 and even ! The price of such equipment used in the field of security, varying between 10,000 and 40,000 francs! To control the functions of the camera (and zoom movements, eventually), the t plupar systems professionals working with cable connections.

The referral system operated by radio
To our knowledge, there is no such system completely controlled by radio. Not even the most sophisticated applications. This is the reason that motivated this study. A sort of challenge to all security professionals and for the pleasure that you can achieve, at a reasonable cost, a device that does not exist commercially.
This assembly, we want to say, offers all the features required by a professional use.
The system that we present in these pages consists of a remotely controlled steerable camera and its remote.
The orientation unit includes a remote receiver coded, operating at 868 MHz, capable of controlling three channels in a linear fashion.
Two of these channels are used to drive the two actuators necessary to orient the camera, the third is not used and remains available to control other mechanisms (such as zoom).



Two other channels, ON / OFF, are also available and can control two additional outputs.
The device also includes a television transmitter 50 mW, which transmits on VHF channel H2 image filmed by the video camera.
In this way, the camera remotely steerable requires no cable connection, or for controls, or for sending pictures. The only cable used is the power cable! The guidance unit is controlled remotely by a special remote control that uses a 868 MHz transmitter and a special coding, managed by a microcontroller.
For moving the camera on two axes, we use two sliding controls, while controlling the zoom is possible entrusted to a conventional potentiometer.
Finally, two buttons control the output ON / OFF.
The scope of the system is around 100 meters. Of course, this scope is always a function of working conditions, possible disruptions present in the area of quality antennas and how they were positioned, etc..
The scope is certainly lower than that of conventional transmission systems because, despite working frequencies completely different and very distant from each other, there is a minimum of mutual influence which causes degradation of the sensitivity of the receiver modules.
The block diagram of the system, given in Figure 1, lets see what we have just explained. On the screen you can see the filmed image and, using the remote, you can move the camera to frame the area of interest.
Our camera orientation unit is equipped with a remotely controlled video camera miniature color very light, more precisely, the model Panasonic CCD chip set with FR149.
This camera offers excellent results in terms of quality because the objective is perfectly suited to our application.
Of course, the use of a zoom would be truly "the icing on the cake" but, unfortunately, the price of cameras so equipped is still prohibitive.
Note, moreover, that the system we have made to operate the video camera can also be used in many other applications, not necessarily related to the field of video surveillance.
The presence of a third linear channel as well as two outputs ON / OFF makes this system even more flexible.
For moving the camera, we used two actuators, generally used in building model boats and planes (see Figure 2).
It seemed like the easiest solution, especially the most economical alternative is to use stepper motors. In fact, the results confirmed the validity of the initial choice.
After this long but necessary introduction, are now entering the heart of the matter by analyzing, first, the schema of the remote control unit shown in figure 3.

Figure 1: Block diagram of the camera remotely adjustable.

Figure 2 : Photo of actuators used in our design.


The analysis of pattern orientation unit remote

Figure 3 : Electrical diagram of the orientation unit remotely.

Those expecting a complex circuit to be in their charge. As you can see, through the use of a microcontroller and three hybrid modules, everything is reduced to very little! Few, very few components, so a scheme that comes down to a skeleton! The video unit program consists of modules Aurel U2 and U3.
The signal, which comes from the camera reaches the transmitter input TXAV (U2) which emits a VHF signal to a power of 2 mW on the channel H2 (224 MHz), modulated in a timely manner with the signals audio / video input.
In our case, the audio is not used, because the camera we use has no microphone.
The VHF output (pin 11) can be directly connected to the transmitting antenna (if one is content with 2 mW) or, as in our case, connected to the input of a power module Aurel MCA (U3 ), which delivers more than 50 mW output.



The transmitting antenna, a simple piece of enameled wire sufficiently rigid 38 cm, is connected to pin 15 of U3.
The module requires a power supply voltage of 12 VDC, which is drawn from the supply terminal.
The TX-AV by cons, requires 5 volts available at the output of 7805 (U1).
For the power of the camera, we have provided a jumper (JP1) to choose between two voltages, 12 or 5 volts.
Most video cameras running, in effect, with 12 volts, but there are still some models operate with a voltage of 5 volts, as is the case of the FR149 used in this circuit.
In the lower part of the scheme, is shown receiving unit and decoding the signal. This unit consists of a hybrid receiver module and a microcontroller.
Is used as a receiver, a brand new module Aurel superheterodyne operating at 868 MHz.
We decided to do our work on this frequency remote control rather than the usual 433.92 MHz for three reasons: the higher frequency difference with the 224 MHz TX-TV, the presence of less noise on this new band and Finally, the availability of modules working on that frequency.
The signal received by the antenna (a piece of wire enameled wire is sufficiently rigid to 8.5 centimeters) is amplified and modulated by the hybrid U5. Thus we find the same train of pulses that generated by the remote on its pin 14.
This digital signal is sent to Pin 4 (GP3), configured as input, the microcontroller U6 which is responsible for developing our requirements. U6 is a preprogrammed PIC 12C672.
The pulse train contains information about the state that should take 5 times.
So to understand how this circuit, we must briefly illustrate the characteristics of actuators used and the protocol information broadcast.

The actuators
The actuators, which are typically used in model for operating the moving parts consist of a small electric motor, a reducer, a translator position, and an electronic control circuit.
These devices, such as stepper motors, are able to rotate in one direction or the other with high precision.
The maximum rotation angle depends on the characteristics of each device.
There are drives with rotational angle of 60, 90, 180, 270 degrees, etc.. but the control system is the same for all versions and, moreover, it is much simpler than stepper motors.
The service valve actuators are operated by three son: ground, positive power and signal.
The input signal is applied a train of pulses with a duration of between 1 and 2 milliseconds with a duty cycle which must be at or below 50%.
In the first case, the axis is positioned entirely on one side in the second case, the opposite side.
Of course, if we send a pulse of 1.5 milliseconds to the actuator, the axis is positioned exactly in the center.
When the axis is at rest, consumption of the booster is a few milliamps, while when in motion, under stress, the consumption is 100, 200, 300 or 400 mA.
When the pulse stops, the device retains its position.
To control the entry of actuators, a signal of very low intensity is sufficient, the order of fractions of a milliamp.
In our circuit, we use actuators with the maximum excursion of plus or minus 60 degrees.
However, the duration of the pulses generated is between 1.25 and 1.75 milliseconds, the actual trip will be plus or minus 30 degrees.

Control actuators
The protocol used to send data on the position of the actuators is another word that consists of six bytes.
The first, the header or header, contains an identification character sets, while the last or "footer" is the amount of control or "check sum".
The second, third and fourth byte represent the values for the position of the actuators.
The fifth, in turn, contains all information on both outputs ON / OFF.





For example, if you place the first linear potentiometer on the remote control center, the value of the second byte of the word will be transmitted 127.
At the reception, this value will be recognized by U6 and sent to the output GP5 which will generate a pulse of 1.5 milliseconds, ensuring that the actuator is placed exactly in the center position.
By moving the linear potentiometer all the way up, the value of the second byte from 127 to 255, which determines a variation of the pulses generated 1.5 to 1.75 msec with the consequence, the rotation of 30 degrees to the right of the centerline of the booster.
Of course, if you move the slider completely linear down, the actuator will move from 30 degrees to the left.
Simple, right?
The operation of pins 3 and 5 of U6 (GP2 and GP4) actuators that control the others is similar.
Regarding the two outgoing auxiliary parts whose level can only be low or high, the corresponding information is contained in the fifth byte and depends, of course, the state of two buttons mounted on the remote.
Pressing P1, AUX1 output will increase from 0 to 1 and remain in this state until the button will remain depressed.
The operation of the AUX2 output is quite similar.
To complete it, found in the circuit of the remote unit to another 5-volt voltage regulator (U4) and a series of smoothing capacitors (C1, C2, C3, C4 and C5).
We preferred to split the 5 volt line to avoid possible interference between the servo circuit and that of the TV channel.
It works with a voltage of 12 VDC, preferably stabilized.
Total consumption is about 300 mA with peaks of 1 amp for the activation of the actuators.
Now analyze the electrical diagram of the remote. It is even easier than before.

Figure 4 : Installation diagram of components of the orientation unit remotely.

Figure 5: Photo of the prototype orientation unit remotely. The printed circuit unit this remote guidance, center, a cut which hosts one of the two actuators. Both sections of the printed circuit board (that of the transmitter and the one that controls the actuators) are placed on opposite sides of the circuit, thereby reducing the maximum interference.

Figure 6 : Design, scale 1, the printed circuit unit remote guidance.


List of components of the unit orientation Remote
R1 = 100 Ω
R2 = 100 Ω
C1 = 1000 uF 16 V electrolytic
C2 = 100 nF multilayer
C3 = 1000 uF 16 V electrolytic
C4 = 1000 uF 16 V electrolytic
C5 = 100 nF multilayer
C6 = 1000 uF 25 V electrolytic
C7 = 100 nF multilayer
C8 = 1000 uF 25 V electrolytic
U1 = 7805
U2 = TX-AV module Aurel
U3 = MCA booster module Aurel
U4 = 7805
U5 = RX868 MHz module Aurel
U6 = μC preprogrammed PIC12C672 MF353

Others:
1 Terminal 2 poles
2 Servo mod. HS-81
1 Support 2 x 4-pin IC
20 Spindles support band scored
1 Cavalier Computer
1 cup 50 cm enamelled wire 15/10
1 PCB ref. S353


Figure 7 : Design elements necessary to achieve the orientation unit remotely.

Figure 8 : The assembly of various mechanical elements to allow the orientation of the camera.

Figure 9: Here is how to present our steerable camera remotely once assembly is complete. In the case of ceiling mounting (see Figure 17), the circuit must be set against that ceiling with four spacers. In this way, the video camera and the guidance system which operates, are found below, which allows users to frame a large area without hindrance. The two pieces of wire used as an antenna are welded on opposite sides of the PCB. These antennas can be bent to reduce the size of the system but it will always be at the expense of reach. As with all RF assemblies, the son of connecting the camera and those of the actuators should be very short so that they do not behave like antennas.

Figure 10 : It is possible, to limit the potential for interference due to the proximity of the RF circuits are shorted, son of the actuators. But be careful not to cut too short, which prevents proper orientation of the camera.


The study of the remote control diagram

Figure 11: Wiring diagram of the remote.

As we can see the wiring diagram of the remote, in Figure 11, the microcontroller U2, a preprogrammed PIC12C672, is the heart of this circuit. It generates the data described above and sends it to the transmitter hybrid U3, Aurel module that works at 868 MHz and is capable of delivering a power of 10 mW with a supply voltage of 5 volts.
The data is not generated continuously, but only in the presence of a variation of the five entries. So, under normal conditions, the microcontroller generates no signal and the transmitter remains off.
If, for cons, it changes the status of one of five inputs (moving, for example, a linear potentiometer or lightly pressing a button), U2 sees this change and sends, for about 3 seconds the word six bytes previously described.
This data is transmitted serially at a rate of 2 kilobits to U3, which is responsible for the spread. The resistive values of the potentiometers are converted into digital data by the analog / digital (A / D) contained in the microcontroller U2.
As we have only one A / D converter, it is used to read sequentially pins 7, 6 and 5 (GP0, GP1 and GP2).
It works with a supply voltage of 5 volts available at the output pin of the regulator U1.
A voltage between 9 and 15 VDC can be applied to the input.
At rest, the consumption is only a few milliamps to 30 milliamps passing during transmission.
As an antenna, you can use a piece of enameled wire is sufficiently rigid for a length of 8.5 (fourth wave) or 17 cm (half wavelength).
It remains for us to look after the completion of the two devices.

The practical realization
The construction of the remote unit orientation
To make the referral system, we used four pieces of epoxy double-sided, mounted as show in Figures 7 and 8.
The two smaller, that is to say those who support the camera, must be welded together at 90 degrees as in Figure 8a. This can be done using a conventional soldering iron.
The camera should be mounted on the piece and performed as shown in Figure 8b.
It must then assemble the two biggest pieces as shown in Figure 8c and implement actuators as shown in Figure 8d.
All the camera must be fixed to the axis of the first booster, which will give a result identical to that of Figure 8e.
The solution we propose is certainly one of the easiest to achieve using tools found in any electronics laboratory.
The printed circuit unit remote guidance, given in Figure 6, receives all the component parts. It has a cutout which must be fixed the second servomotor.
The result is visible on the photo in Figure 9.
If we look at the layout diagram of the components of Figure 4 and the photo of the prototype of Figure 5 reveals that all components of the sending unit located on the right, while those for the control actuators are mounted on the left.
In this way, we arrive at best limit the coupling of two supply lines, minimizing interference due to operation of servo motors and two RF sections.
This is not a coincidence that the two antenna outputs are on opposite sides of the circuit.
The assembly of some components and pre-programmed microcontroller presents no difficulty.
After you have obtained or made the printed circuit of Figure 6, first install the lowest and ending with the highest. Pay attention to the elements which are polarized.
The hybrid module can be inserted in one direction only, so there is no possibility of being wrong.
As the son of the outgoing video camera and two servos must be connected to the corresponding PCB.
We recommend you attach the two voltage regulators on a small piece of aluminum to help dissipate heat.
Finally, move the jumper that controls the voltage of the video camera on the correct value (5 volts in the case of the video camera FR149).
We can then supply the whole with a source capable of 12 volts fournier stabilized, and a maximum current of 1 A.
The construction of the remote must first make or purchase the printed circuit whose design is shown in Figure 14.
By helping the layout diagram of Figure 12 and the photo of the prototype of Figure 13, you mount all components always starting from the lowest to the highest finish by. Make sure the meaning of polarized components.
Two sliders control the movements of the actuators.
To control the third channel, cons, we used a traditional potentiometer.
Two buttons control the PCB output ON / OFF.
The circuit requires no calibration and, if the installation is done properly, it will work when you diet.

Figure 12 : Diagram of component layout on the remote.

Figure 13: The remote, once assembly is complete. The use of linear potentiometers can act with precision actuators that operate the video camera. The third channel, also linear, is controlled via a rotary potentiometer (R5). It is not used in this application but it can be used to control a possible zoom. The push for printed circuit control two channels ON / OFF. These channels are not used here.

Figure 14 : Design, scale 1, the printed circuit on the remote.

List components of the remote control
R1 = 10 kW
R2 = 10 kW
R3 = 5 kΩ pot. zip
R4 = 5 kΩ pot. zip
R5 = 4.7 kΩ potentiometer it green.
C1 = 1000 uF 16 V electrolytic
C2 = 1000 uF 16 V electrolytic
C3 = 100 nF multilayer
C4 = 100 nF multilayer
D1 = 1N4007 diode
U1 = 7805
U2 = μC preprogrammed PIC12C672 MF352
U3 = 868 MHz TX module Aurel
Push it to P1 = NO
Push it to P2 = NO

Others:
1 Terminal 2 poles
1 Support 2 x 4-pin IC
1 cup 20 cm enamelled wire 15/10
1 PCB ref. S352


Verifying operation

Figure 15 : To transmit images, the camera is connected to hybrid modules VHF TV Aurel. In this photo, the amplifier 50 mW.

Figure 16: To make and receive orders, the system uses hybrid modules Aurel 868 MHz. Here, the RX-868.

Figure 17 : The camera in its clear plastic dome.

Monitor whether the first video transmitter works properly adjusting a television set on channel VHF H2. The coverage of the camera should appear on the screen.
Then try to act on the sliding of the remote control by verifying that the two actuators are moving properly. These checks are completed, we can then perform tests of significance by trying to position the antennas so as to obtain the best results.
The steerable camera can be remotely installed n'impor you where, even if the best position is undoubtedly the ceiling, inside a clear plastic dome (see Figure 17).

A little clarification
If remote monitoring systems can be used without restriction in the home, provided they respect the privacy of others, it is not the same as regards their use in public places.
This use is subject to certain rules. We therefore recommend that you consult the legislation in force if you want to install such a system in your business.